Do you know the best knee braces for arthritis?

Depends, if you just looking for support you can get a neoprene brace with some side stays. It will keep the joint warm and the compression will give you the "feeling" of support. If one of the compartments in your knee is more worn that the other you can try what's called and "unloader" which will unload stress from the affected arthritic compartment to the less stressed compartment. For certain degrees of arthritis with certain angularity of the knee, (varus/valgus, or bowlegged or knocked-kneed) it can make a difference. All these you want to check with your doctor because some will require a prescription.